In this episode of The Athletes Compass, the team sits down with Siren Seiler-Viken—researcher, coach, and emerging voice in Hyrox performance science. From her early years as an elite dancer to national-level distance running and now competitive Hyrox racing, Siren shares how sustainability, intelligent planning, and aerobic development form the foundation of hybrid performance. The conversation explores the physiological demands of Hyrox, why running may be the most overlooked performance driver, how to balance strength and endurance without sabotaging adaptation, and why pacing strategy can make or break your race. Whether you're a competitive athlete or new to hybrid fitness, this episode delivers practical, science-backed insight on building performance that lasts.

1. Running accounts for ~60% (or more) of Hyrox race time — aerobic development is foundational.
2. Wall balls produce the highest physiological strain due to total-body demand + accumulated fatigue.
3. Hyrox is primarily an endurance event with strength elements—not the other way around.
4. Max strength matters—but mostly to raise your ceiling so race loads feel submaximal.
5. Muscle mass can become a liability if it compromises running economy.
6. A pyramidal or polarized endurance approach builds sustainable fitness.
7. Double-threshold training can be effective for advanced athletes when carefully structured.
8. Splitting strength and endurance sessions by 5–6 hours reduces interference effects.
9. Pacing is critical—early overexertion can derail the entire race.
10. Variation in endurance modalities (run, row, ski) supports durability and injury prevention.
11. Hyrox’s appeal lies in accessibility, inclusivity, and standardized global competition.

00:00 – Injury Prevention & Mixing Modalities

02:07 – From Elite Dance to National-Level Running

07:57 – What Is Hyrox? Format & Demands

12:03 – Why Running Determines Hyrox Performance

16:25 – Why Wall Balls Break Athletes

22:13 – Is Max Strength Overrated in Hyrox?

26:25 – Programming: Base Building, Strength & Specificity

52:35 – Double Threshold & Concurrent Training

46:05 – The Rise of Hyrox & Olympic Potential

• Siren Seiler-Viken Coaching
• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai | Nordic Performance Lab